Safety assessment of 4-week oral intake of proanthocyanidin-rich grape seed extract in healthy subjects

- The safety of oral grape seed extract was assessed in 29 healthy Japanese subjects.
- The subjects received daily doses of up to 2500 mg grape seed extract for 4 weeks.
- The extract was safe and well tolerated, according to lab tests and recorded events.

A clinical study was conducted to assess the safety and tolerability of oral doses of proanthocyanidin-rich grape seed extract (GSE) in healthy Japanese adult volunteers. In an open-label, 4-week toxicity test, 29 subjects daily received 1000, 1500, or 2500 mg GSE orally. Serum Fe levels of two subjects in the 2500 mg GSE group decreased to 61 and 60 μg/100 mL from 205 and 182 μg/100 mL at baseline respectively, at second week of GSE consumption; these values are low but within the normal range for the Japanese population. Two weeks after completing the 4-week course of GSE ingestion, the serum Fe levels of both subjects returned to near baseline levels (210 and 189 μg/100 mL). No subject discontinued the study. Oral intake of GSE up to 2500 mg for 4 weeks was found to be generally safe and well tolerated in humans. Research with a larger number of subjects is required to confirm these findings.